Floating systems of the barge type, especially for drilling in deep water

ABSTRACT

The system comprises a base in the shape of a polygon with flattened hollow cross-section. Piers are welded on this space, inclined and arranged as a crown, the assembly supporting an upper platform. The polygon shape base can be replaced by a type of catamaran.

United States Patent 191 Vilain 1 1 Oct. 15, 1974 FLOATING SYSTEMS OF THE BARGE 3,154,039 10/1964 Knapp 114 .5 D

TYPE, ESPECIALLY FOR DRILLING IN 3 227 253 2; E eopo DEEP WATER 3,575,005 4/1971 S arr ng [75] Inventor: Robert Vilain, Maisons-Alfont, 9 7 Horton France 3,580,207 5 1971 Pangalila 114/.5 D

[73] Assignee: Enterprise DEquipernent Maaniques Hydrauliques Primary ExaminerTrygve M. Blix England Assistant ExaminerD C. Butler [22] Filed: May 9, 1972 Attorney, Agent, or FirmStevens, Davis, Miller &

Mosher [21] App]. No.: 251,684

[30] Foreign Application Priority Data [57] ABSTRACT May 14, 1971 France.....' 71.17522 The system comprises a base in the shape of a polygon [52] US. Cl. 114/.5 D, 61/465 with flattened hollow crossflection Piers are welded [51] Int. Cl B63b 35/44 on this Space inclined and arranged as a Crown the [58] Field of Search 14/.5 D, .5 F 45, 230, assembly Supporting an upper platform The polygon 14/123 61/465 shape base can be replaced by a type of catamaran.

[56] References Cited UNITED STATES PATENTS 9 Claims, 11 Drawing Figures McCammon 114/230 FLOATING SYSTEMS OF THE BARGE TYPE, ESPECIALLY FOR DRILLING IN DEEP WATER The invention relates to floating systems, of the barge type, more especially for drilling (petroleum drilling etc.), especially in deep water.

It is known that, for drilling at sea, the use of columns anchored at the base to the submarine bed has been proposed. However this solution is only suitable for moderate depths.

For greater depths, especially of the order of 100 m and beyond, floating bodies are used, which are kept in position by anchoring chains or other means of this type. In particular, barges are used, which are generally constituted by a floating base, forming for example a hollow crown, of suitable cross-section, on which base is superposed hollow vertical columns of cross-section less than that of said crown, the whole being completed by cross members and wind bracing trellises. Calculation and practice have shown that, in the floating position for which the base is some meters below the level of the water, insensitivity to swell is obtained, by the stabilizing effect arising from the difference in crosssection between the base and the abovesaid columns.

However such an assembly is of rather expensive The invention consists, apart from this main feature,

of certain other features which are preferably used at the same time and which will be more explicitly considered below.

And it relates more particularly to certain types of application (especially those in which it is applied to barges for petroleum drilling), as well as certain embodiments, of said features; and it relates, more particularly again and this by way of new industrial products, to barges including the application of these same features, as well as the special elements adapted for their construction and installations comprising them.

The invention will in any case be more fully understood by means of the additional description which follows, as well as the accompanying drawings, which additional descriptio and drawings are, of course in tended primarily b way of indication and are not to be regarded as in any way limiting.

la the drawings:

FlG. 1 shows diagrammatically in elevation one embodiment of the assembly of a barge, intended for petroleum drilling, constructed according to the invention.

FIGS. 2 to 4 show on a larger scale, respectively in elevation, in plan and in enlarged cross-section along the line lV-lV of HG. 2, the abovesaid embodiment of the barge.

FIGS. 5 and 6 show on a larger scale the details of the weld of the piers to the base of the abovesaid barge.

FIG. 7 shows in plan a phase of the mounting of the base elements.

FIGS. 8 and 9 illustrate, respectively along two perpendicular cross-sections, an operation of welding two elements of the base.

FIGS. 10 and 11, lastly, illustrate similarly to FlGS. 2 and 3 a modification of the invention.

According to the invention and more especially according to that of its types of application, as well as according to those embodiments, of its various parts, to which it would appear that preference should be given, in order for example to construct a barge for petroleum drilling or the like, procedure is as follows or in analogous manner.

This barge comprises firstly, a hollow base 1 forming a float, for example with the shape of a polygon in plan (circular, etc.), the elements of this base having any flattened shape, with a cross-section for example as a trapezium, as illustrated in FIGS. 4 to 6.

To this base, there is made rigid a series of inclined hollow piers 2, arranged so as to form a triangles, which elements, on one hand, are fixed at their lower portion to the base 1, and on the other hand, are connected two by two at their upper portion, where the tops of the triangulation thus produced can be connected by linking elements 3.

The piers 2 can have, as shown, a certain inclination towards the inside of the barge, which contributes to Purely by way of indication, for a barge whose width D (FlG. 2) would be of the order of 100 m, width L of the base 1 would be of the order of 12 m and the diame ter of the piers 2 of the order of 5 m. The height h of the barge is of the order of 40 m.

Such an assembly, once completed, appears as shown in FIG. 1, with a certain depth of immersion. Anchoring is effected by means of chains 11 (FIG. 1) or any other means.

For the assembly, it is advantageous, taking into account the dimensions of the assembly, to effect this on site.

Thus to this end there is first constructed in the workshop elements such as shown at a in FIG. 7, comprising a side of the base polygon and two adjacent half sides, each of these unit elements having welded thereto, tubular feet 6 intended to constitute the beginning of the piers 2. FIGS. 5 and 6 show, in one embodiment, the various welding points, which maintain the fluidtightness of the base I.

These unit elements being brought to the site, for example towed as floats (the ends being plugged by any closing elements, temporary or not), they are assembled by welding, along connecting planes 7 (FlG. 7), by

' using any underwater welding device with welds as, il-

lustrated in FIGS. 8 and 9, in a watertight welding chamber8.

The base 1 being thus constructed, there is then welded, on the feet or roots 6, the piers 2, previously constructed, in the form of two V twin elements, in the workshop, and brought to the work site.

The rest of the assembly is carried out normally by the usual means.

It should be noted that the depth of immersion can if necessary be adjusted by ballasting in the hollow elements of the barge.

Propulsive means can if necessary be provided on the said barge, means such as shown in FlG. 4 and consisting of one or several screws 9 actuated by motors 10 arranged inside the base 1. There would for example be six motors and screws of this type arranged in six different azimuths, with the possibility of actuating them separately.

There is shown in FIGS. 10 and 11, a modification of the invention in which the lower tubular system is arranged in the shape of two hulls 13 forming a catamaran offering doubled resistance to immersion, each of these hulls being shapable in the style of a boat.

These two hulls 13 will be connected. to one another by two cross-beams 14 of large cross-section.

Hence in this assembly 13, 14, the lower ends of the hollow piers 2 are fixed. This fixing, which is effected by welding, is preferably done at the same time on the upper surface of the elements 13, 14 and on their lower surface or over the whole cellular structure comprised by these elements, this on the same principle as that already illustrated in FIGS. 5 and 6. it is understood also that any reinforcements could be provided at these places of fixing, so that the strength is completely ensured.

As a result of which, and whatever the embodiment adopted, barges can be constructed whose assembly and operation emerge sufficiently from the foregoing for it to be unnecessary to dwell further on their subject and which have, with respect to pre-existing installations of the type concerned, numerous advantages, especially:

that of enabling considerable simplification of the assembly, hence of its erection,

and that of-enabling, if desired, the transportation to the work site of the various elements to be realizable entirely by towing.

As is self-evident, and as emerges already from the foregoing, the invention is in no way limited to those types of application and embodiments which have been more especially considered; it encompasses, on the contrary, all modifications.

I claim:

1. Floating system, of the barge type, said system having a horizontal support and for its buoyancy, stability and cross-bracing. means consisting essentially of an assembly of two groups of hollow tubular elements, a first said group of tubular elements forming an annular shaped polygon base in a horizontal plane, and a second said group of hollow tubular elements constituting piers rising obliquely from said base, said assembly forming a cross-braced floating structure, said second group of hollow tubular elements extending between said base and said horizontal support.

2. System according to claim 1, wherein the piers are slightly inclined towards the inside of the annular base.

3. System according to claim 1, wherein said piers are arranged to form triangles, said triangles having-tops arranged around an annular contour and linking elements connecting said tops.

4. System according to claim 1, wherein said piers form a trellis, and wherein said horizontal support is a platform supported by the upper portion of the trellis.

5. System according to claim 1, wherein the base is constituted by a plurality of welded elements each forming one of the sides as well as the two adjacent half-sides of the polygon base.

6. System according to claim 5, wherein said welded elements of the'base are welded under water.

7. System according to claim 5, wherein the constituent elements of the base comprise tubular feet to serve as roots for the piers.

8. System according to claim 1, wherein the annular shaped base is arranged in the form of a catamaran, having two parallel hulls connected by transverse elements.

9. Floating system according to claim 1, comprising a drilling rig, wherein said cross-braced structure forms a trellis. 

1. Floating system, of the barge type, said system having a horizontal support and for its buoyancy, stability and crossbracing means consisting essentially of an assembly of two groups of hollow tubular elements, a first said group of tubular elements forming an annular shaped polygon base in a horizontal plane, and a second said group of hollow tubular elements constituting piers rising obliquely from said base, said assembly forming a cross-braced floating structure, said second group of hollow tubular elements extending between said base and said horizontal support.
 2. System according to claim 1, wherein the piers are slightly inclined towards the inside of the annular base.
 3. System according to claim 1, wherein said piers are arranged to form triangles, said triangles having tops arranged around an annular contour and linking elements connecting said tops.
 4. System according to claim 1, wherein said piers form a trellis, and wherein said horizontal support is a platform supported by the upper portion of the trellis.
 5. System according to claim 1, wherein the base is constituted by a plurality of welded elements each forming one of the sides as well as the two adjacent half-sides of the polygon base.
 6. System according to claim 5, wherein said welded elements of the base are welded under water.
 7. System according to claim 5, wherein the constituent elements of the base comprise tubular feet to serve as roots for the piers.
 8. System according to claim 1, wherein the annular shaped base is arranged in the form of a catamaran, having two parallel hulls connected by transverse elements.
 9. Floating system according to claim 1, comprising a drilling rig, wherein said cross-braced structure forms a trellis. 